Study on design optimization of a crankshaft bearing considering crankshaft strength for an internal combustion engine

Abstract

The effect on a crankshaft was not generally considered in the current optimum design of a crankshaft bearing for an internal combustion engine, but the corresponding relation between the dimensions of a crankshaft bearing and those of a crankshaft journal exists. In this article, the crankshaft-bearing system of a four-stroke, four-cylinder internal combustion engine was taken as the research object, and the optimum design of crankshaft bearings considering crankshaft strength was carried out. The necessity of considering crankshaft strength in the optimum design of the crankshaft bearings was studied. Crankshaft strength was taken as one of the constraints in establishing the model of optimum design of the crankshaft bearings. The particle swarm algorithm was used to optimize crankshaft bearings. The results show that, compared with the design of bearings for the original engine, the calculated 14.21 per cent of the total average frictional power loss of the bearings can be reduced by the optimum design of crankshaft bearings on the condition that crankshaft strength is not exceeded. If the effect on a crankshaft is not considered in the optimum design of crankshaft bearings, although obviously the total average frictional power loss of the bearings is reduced, crankshaft strength cannot meet design demand. Therefore, a reasonable optimum design of crankshaft bearings should consider the whole crankshaft-bearing system and the effect on crankshaft strength.